JP7422570B2 - Work vehicle and control method - Google Patents

Description

The present disclosure relates to a work vehicle and a method of controlling a work vehicle.

Conventionally, as shown in Patent Document 1, a work vehicle having a work implement such as a blade is known. The operator of the work vehicle adjusts the traveling direction of the work vehicle by operating a steering wheel according to the current road surface condition at the work site.

When the work site has a curve, the operator needs to operate the steering wheel and the work equipment in a combined manner in accordance with the curvature of the curve. Such complex operations are extremely sophisticated and delicate.

Japanese Unexamined Patent Publication No. 59-102023

For example, it is possible to reduce the operational burden on the operator by applying to a work vehicle a technique that changes the blade propulsion angle to follow changes in the steering angle based on steering wheel operation.

However, the coefficient of dynamic friction of the wheels of a work vehicle varies depending on road surface conditions and the like. Furthermore, in the case of a motor grader, for example, work may be performed while leaning the front wheels. For this reason, conventionally, it is not possible to determine the exact traveling direction of the work vehicle. Therefore, it is difficult to make the blade propulsion angle accurately follow changes in the traveling direction of the work vehicle.

The present disclosure has been made in view of the above problems, and the purpose is to control a work vehicle and a work vehicle that can accurately follow a blade propulsion angle with respect to changes in the traveling direction of the work vehicle. The purpose is to provide a method.

According to an aspect of the present disclosure, a work vehicle includes a vehicle body and a work machine having a blade. The vehicle body includes a controller that controls the operation of the working machine and an acceleration sensor. The controller controls the blade propulsion angle of the blade based on the output from the acceleration sensor.

According to other aspects of the present disclosure, a work vehicle includes a swing circle, a blade supported on the swing circle, a front frame, a drawbar swingably attached to the front frame and to which the swing circle is attached, and a drawbar mounted on the drawbar. An acceleration sensor is provided, and a controller is provided that controls the blade propulsion angle of the blade by rotating a turning circle based on the output from the acceleration sensor.

According to still another aspect of the present disclosure, there is provided a method for controlling a work vehicle, wherein the work vehicle includes a vehicle body and a work implement having a blade, and the vehicle body includes a controller that controls the operation of the work implement, and an acceleration sensor. and has. The control method includes the steps of a controller receiving a signal output from an acceleration sensor, and a step of controlling a blade propulsion angle of the blade based on the signal.

According to yet another aspect of the present disclosure, there is provided a method for controlling a work vehicle, the work vehicle comprising: a turning circle; a blade supported by the turning circle; a front frame; It includes a drawbar to which a turning circle is attached, an acceleration sensor provided on the drawbar, and a controller. The control method includes the steps of a controller receiving a signal output from an acceleration sensor, and a step of controlling a blade propulsion angle of the blade by rotating a turning circle.

According to the present disclosure, it is possible to accurately make the blade propulsion angle follow changes in the traveling direction of the work vehicle.

FIG. 1 is a perspective view schematically showing the configuration of a motor grader. It is a top view of a motor grader. It is a figure for explaining a blade propulsion angle. It is a figure explaining the outline of composition of a rotation mechanism. FIG. 2 is a conceptual diagram illustrating a leaning operation of a motor grader. FIG. 2 is a functional block diagram illustrating the functional configuration of a control system for a motor grader. FIG. 3 is a flow diagram for explaining the flow of processing executed by the motor grader. FIG. 3 is a diagram for explaining an overview of automatic control of a blade propulsion angle. It is a figure for explaining other installation positions of an acceleration sensor. It is a perspective view showing a bulldozer. It is an enlarged view of the main parts of the bulldozer. It is a figure for explaining the blade propulsion angle in a bulldozer.

Hereinafter, embodiments will be described based on the drawings. In addition, in the following description, the same parts are given the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[Embodiment 1]
A motor grader will be described as an example of a work vehicle. FIG. 1 is a perspective view schematically showing the configuration of a motor grader 100 based on an embodiment. FIG. 2 is a plan view of motor grader 100 shown in FIG.

As shown in FIGS. 1 and 2, a motor grader 100 according to the embodiment includes a vehicle body 2 and a working machine 4. As shown in FIGS. The vehicle body 2 mainly includes a front wheel 11 that is a running wheel, a rear wheel 12 that is a running wheel, a rear frame 21, a front frame 22, and a cab 3. The front wheels 11 have one wheel on each side, and include a right front wheel 11R and a left front wheel 11L. Although the drawing shows running wheels consisting of two front wheels 11, one on each side, and four rear wheels 12, two on each side, the number and arrangement of the front wheels and rear wheels is not limited to this.

The motor grader 100 includes components such as an engine disposed in an engine room 6. Work machine 4 includes a blade 42 . The motor grader 100 can use the blade 42 to perform tasks such as leveling the ground, removing snow, light cutting, and mixing materials.

In the explanation of the figures below, the direction in which the motor grader 100 travels straight is referred to as the front-rear direction of the motor grader 100. In the longitudinal direction of motor grader 100, the side where front wheel 11 is arranged with respect to working machine 4 is defined as the front direction. In the front-rear direction of motor grader 100, the side where rear wheel 12 is arranged with respect to working machine 4 is defined as the rear direction. The left-right direction or side of motor grader 100 is a direction perpendicular to the front-back direction in plan view. Looking forward, the right and left sides in the left and right direction are the right direction and left direction, respectively. The vertical direction of motor grader 100 is a direction perpendicular to a plane defined by the front-rear direction and the left-right direction. In the vertical direction, the side with the ground is the bottom, and the side with the sky is the top.

In the following figures, the front-back direction is indicated by arrow X in the figure, the left-right direction is indicated by arrow Y in the figure, and the up-down direction is indicated by arrow Z in the figure.

The rear frame 21 is arranged behind the front frame 22. The rear frame 21 supports an exterior cover 25 and components such as an engine disposed in the engine compartment 6. The exterior cover 25 covers the engine compartment 6. For example, each of the two rear wheels 12 on each side is rotatably attached to the rear frame 21 by driving force from the engine.

The cab 3 is mounted on a rear frame 21. The cab 3 has an interior space for an operator to board, and is arranged at the front end of the rear frame 21. The cab 3 may be mounted on the front frame 22.

Inside the cab 3, operating units such as a steering wheel for steering the front wheels 11, a gear shift lever, an operating lever for the working machine 4, a brake, and an accelerator pedal are provided. When the operator operates the steering wheel, the direction of the front wheels 11 is changed, and the motor grader 100 can change the direction of travel. The steering angle of the front wheels 11 changes by operating the steering wheel. A steering lever may be provided instead of the steering wheel so that steering can be performed by operating the lever. Alternatively, it is also possible to provide a configuration in which both a steering wheel and a steering lever are provided.

The front frame 22 is attached to the front of the rear frame 21. The front wheels 11, for example one on each side, are rotatably attached to the front end of the front frame 22. Further, a counterweight 51 is attached to the front end of the front frame 22.

The work machine 4 mainly includes a drawbar 40, a turning circle 41, a blade 42, a turning motor 49, and various cylinders 44 to 48.

The front end of the drawbar 40 is swingably attached to the tip of the front frame 22. A rear end portion of the drawbar 40 is supported by the front frame 22 by a pair of lift cylinders 44 and 45. By the synchronized expansion and contraction of the pair of lift cylinders 44 and 45, the rear end portion of the drawbar 40 can move up and down with respect to the front frame 22. Further, the drawbar 40 can be swung up and down about an axis along the vehicle traveling direction by different expansion and contraction of the lift cylinders 44 and 45.

A drawbar shift cylinder 46 is attached to the front frame 22 and the side end of the drawbar 40. By expanding and contracting the drawbar shift cylinder 46, the drawbar 40 can be moved left and right with respect to the front frame 22.

The turning circle 41 is rotatably attached to the rear end of the drawbar 40. The turning circle 41 can be driven to turn clockwise or counterclockwise with respect to the drawbar 40 by a turning motor 49 when viewed from above the vehicle. By the turning drive of the turning circle 41, the inclination angle (hereinafter also referred to as blade propulsion angle) of the blade 42 with respect to the front frame 22 in plan view is adjusted. In the working machine 4 shown in FIG. 2, the turning circle 41 is at a position rotated counterclockwise in plan view compared to the arrangement shown in FIG. Therefore, the blade 42 shown in FIG. 2 is placed in a different position than the blade 42 shown in FIG.

The blade 42 is supported by the turning circle 41. The blade 42 is supported by the front frame 22 via a turning circle 41 and a drawbar 40.

The blade shift cylinder 47 is attached to the turning circle 41 and the blade 42, and is arranged along the longitudinal direction of the blade 42. The blade shift cylinder 47 allows the blade 42 to move laterally with respect to the turning circle 41.

A tilt cylinder 48 is attached to the turning circle 41 and the blade 42. By expanding and contracting the tilt cylinder 48, the blade 42 can swing about an axis extending in the longitudinal direction of the blade 42 with respect to the turning circle 41, and can change its direction in the vertical direction.

As described above, the blade 42 can move up and down relative to the vehicle through the drawbar 40 and the turning circle 41, swing around the axis along the direction of vehicle travel, change the inclination angle in the front-rear direction, and change the inclination angle in the left-right direction. The blade 42 is configured to be able to move and swing around an axis extending in the longitudinal direction of the blade 42.

Motor grader 100 further includes an acceleration sensor 9. In this example, the acceleration sensor 9 is attached to the vehicle body 2. Acceleration sensor 9 is attached to front frame 22. Acceleration sensor 9 is attached to the upper surface of front frame 22.

The acceleration sensor 9 may be attached to the lower surface or side surface of the front frame 22. Alternatively, the acceleration sensor 9 may be attached inside the front frame 22.

The main controller (FIG. 6) of the motor grader 100 can obtain acceleration on the horizontal plane (on the XY plane) from the acceleration sensor 9. The main controller can determine the traveling direction and speed of the vehicle body 2 (motor grader 100, front frame 22) based on the acquired acceleration.

An inertial measurement device may be used instead of the acceleration sensor 9. The inertial measurement device includes at least a gyro sensor and an acceleration sensor. The inertial measurement device is also referred to as an IMU (Inertial Measurement Unit), an INU (Inertial Navigation Unit), an IGU (Inertial Guidance Unit), and an IRU (Inertial Reference Unit).

FIG. 3 is a diagram for explaining the blade propulsion angle.

As shown in FIG. 3, drawbar 40 moves in the direction of arrow 903. The turning circle 41 rotates in the direction of arrow 902. Blade 42 moves in the direction of arrow 901. The blade 42 rotates around the rotation axis C1 by the rotation drive of the rotation circle 41. As the blade 42 rotates around the rotation axis C1, the blade propulsion angle θ varies.

The first imaginary line M1 is a line that is perpendicular to the rotation axis C1 and parallel to the blade 42 (center line K of the blade 42). Further, the second imaginary line M2 is a line that is perpendicular to the rotation axis C1 and perpendicular to the first imaginary line M1. Note that the first virtual line M1 and the second virtual line M2 are lines parallel to the XY plane.

The blade propulsion angle θ is the angle between the front frame 22 and the blade 42. The blade propulsion angle θ is the angle between the axis J of the front frame 22 and the center line K of the blade 42. The blade propulsion angle θ is the angle between the axis J of the front frame 22 and the first imaginary line M1. The blade propulsion angle θ is the inclination angle of the blade 42 with respect to the longitudinal direction of the front frame 22.

In this example, the blade propulsion angle θ in the state shown in FIG. 3 is set to a positive value. When the drawbar 40 is in the neutral position as shown in FIG. 3, the blade propulsion angle θ is defined as a positive value when the right end of the blade 42 is located closer to the front wheel than the left end. The blade propulsion angle θ when the left end of the blade 42 is located closer to the front wheel than the right end is defined as a negative value.

The absolute value of the blade propulsion angle θ is typically set between 45° and 60°. Note that the range of the absolute value of the blade propulsion angle θ is 0° or more and 90° or less.

The motor grader 100 is capable of articulate operation in which the front frame 22 is rotated with respect to the rear frame 21. The motor grader 100 includes a rotation mechanism for performing an articulate operation. FIG. 4 is a diagram illustrating the outline of the configuration of the rotation mechanism.

As shown in FIG. 4, the front frame 22 and the rear frame 21 are connected by a connecting shaft 53. The connecting shaft 53 extends in the vertical direction (in the direction perpendicular to the plane of the paper in FIG. 4). The connecting shaft 53 is arranged at a substantially lower position of the cab 3 (not shown in FIG. 4).

The connecting shaft 53 connects the front frame 22 to the rear frame 21 so as to be rotatable relative to the rear frame 21 . The front frame 22 is pivotable in both directions relative to the rear frame 21 about the connecting shaft 53. The angle formed by the front frame 22 with respect to the rear frame 21 is adjustable.

The rotation of the front frame 22 with respect to the rear frame 21 is performed by expanding and contracting the articulate cylinder 54 connected between the front frame 22 and the rear frame 21 by operation from the cab 3. An angle sensor 38 is attached to the rear frame 21 and detects the articulate angle, which is the rotation angle of the front frame 22 with respect to the rear frame 21.

By rotating (articulating) the front frame 22 with respect to the rear frame 21, the turning radius when the motor grader 100 turns can be made smaller, and it is possible to perform trench digging and trench cutting work by offset running. be. Offset running means that the motor grader 100 is driven straight by rotating the front frame 22 with respect to the rear frame 21 and rotating the front wheels 11 with respect to the front frame 22 in opposite directions. Say something.

FIG. 5 is a conceptual diagram illustrating leaning operation of the motor grader 100.

FIG. 5A shows the state of the front wheel 11 in left leaning motion. A case is shown in which the front wheel 11 is tilted to the left by an angle P as the leaning cylinder 92 expands and contracts. As a result, the turning radius when turning left becomes smaller.

FIG. 5(B) shows the state of the front wheel 11 during right leaning motion. A case is shown in which the front wheel 11 is tilted rightward by an angle Q as the leaning cylinder 92 expands and contracts. As a result, the turning radius when turning to the right becomes smaller.

FIG. 6 is a functional block diagram illustrating the functional configuration of the control system of motor grader 100.

FIG. 6 shows the relationship between the main controller 150 and other peripheral devices. Here, the peripheral devices include an acceleration sensor 9, an angle sensor 38, a work implement lever 118, a switch 120, a steering wheel 129 for steering the front wheels 11, a sensor 171, a swing motor 49, and a lift cylinder. 44, 45, a drawbar shift cylinder 46, and an articulate cylinder 54.

Note that the work implement lever 118, switch 120, and steering wheel 129 are provided inside the cab 3.

Main controller 150 is a controller that controls motor grader 100 as a whole. The main controller 150 includes a CPU (Central Processing Unit), a nonvolatile memory in which programs are stored, and the like.

Main controller 150 controls control valve 134 and the like. A work machine lever 118, a switch 120, and a steering wheel 129 are connected to the main controller 150. The main controller 150 outputs a lever operation signal (electrical signal) to the control valve 134 according to the operation state of the work implement lever 118.

Control valve 134 is an electromagnetic proportional valve. Control valve 134 is connected to main controller 150. Main controller 150 outputs an operation signal (electrical signal) to control valve 134 according to the operation direction and/or amount of operation of work implement lever 118 . The control valve 134 controls the amount of hydraulic fluid supplied from the hydraulic pump (not shown) to the hydraulic actuator according to the operation signal. Note that the hydraulic actuators include, for example, the swing motor 49, lift cylinders 44, 45, drawbar shift cylinder 46, blade shift cylinder 47, tilt cylinder 48, and the like.

The main controller 150 includes an operation content determination section 151, a memory 155, and a control valve control section 156.

The sensor 171 detects the rotation angle of the turning circle 41 (blade propulsion angle θ). The sensor 171 transmits information on the rotation angle to the control valve controller 156.

The operation content determination unit 151 determines the operation content of the work equipment lever 118 by the operator. The operation content determination section 151 outputs the determination result to the control valve control section 156.

Memory 155 stores various information.

The control valve control unit 156 controls the drive of the swing motor 49 by controlling the control valve 134 according to the magnitude of the current value that is the output operation command. Further, the control valve controller 156 receives information on the circle rotation angle from the sensor 171. The control valve control unit 156 corrects the current value, which is the operation command to the control valve 134, based on the circle rotation angle information from the sensor 171.

Acceleration sensor 9 sends measurement results to main controller 150. Acceleration sensor 9 notifies main controller 150 of acceleration.

The switch 120 is a switch for automatically following a change in the traveling direction of the motor grader 100 in the blade propulsion angle θ. When the operator turns on the switch 120, automatic control of the blade propulsion angle θ using the output from the acceleration sensor 9 is started. Further, when the operator turns off the switch 120, the automatic control of the blade propulsion angle θ is stopped.

Note that as the switch 120, for example, an alternate switch can be used. Further, an operating lever may be provided instead of the switch 120. The specific configuration of the operating device for automatically controlling the blade propulsion angle θ is not particularly limited.

FIG. 7 is a flow diagram for explaining the flow of processing executed by motor grader 100.

Referring to FIG. 7, in step S1, motor grader 100 receives an on operation for switch 120. In this case, switch 120 transmits a signal based on the on operation to main controller 150.

In step S2, main controller 150 determines whether motor grader 100 is running. For example, main controller 150 determines whether motor grader 100 is moving forward.

If it is determined that the vehicle is not running (NO in step S2), main controller 150 determines in step S11 whether an off operation for switch 120 has been received. If it is determined that the off operation has been accepted (YES in step S11), the series of processes ends. If it is determined that the off operation has not been accepted (NO in step S11), the main controller 150 returns the process to step S2.

If it is determined that the motor grader 100 is running (YES in step S2), the main controller 150 calculates an angle α representing the actual traveling direction of the motor grader 100 based on the output from the acceleration sensor 9 in step S3.

In step S4, the main controller 150 calculates the blade propulsion angle θ of the blade 42 based on the output of the sensor 171. In step S5, the main controller 150 subtracts the angle α calculated in step S3 from the blade propulsion angle θ calculated in step S4, thereby subtracting the angle δ (=θ -α). In step S6, the main controller 150 temporarily stores the value of the angle δ in the memory 155 as a target angle γ (fixed value).

In step S7, the main controller 150 determines whether the angle α has changed based on the output from the acceleration sensor 9. If it is determined that the angle α has not changed (NO in step S7), the main controller 150 advances the process to step S10.

If it is determined that the angle α has changed (YES in step S7), the main controller 150 calculates the target value of the blade propulsion angle θ based on the target angle γ and the changed angle α in step S8. The main controller 150 calculates the target value (=γ+α) of the blade propulsion angle θ by adding the angle α to the target angle γ. In step S9, the main controller 150 rotates the turning circle 41 until the blade propulsion angle θ reaches the target value.

In step S10, the main controller 150 determines whether an off operation for the switch 120 has been received. If it is determined that the off operation has been accepted (YES in step S10), the series of processes ends. If it is determined that the off operation has not been accepted (NO in step S10), the main controller 150 returns the process to step S7.

The calculation cycle of the angle α in step S7 is appropriately set in the main controller 150. By shortening the period, followability can be improved.

FIG. 8 is a diagram for explaining an overview of automatic control of the blade propulsion angle θ. Automatic control of the blade propulsion angle θ is performed based on the output from the acceleration sensor 9. The xy coordinate system used in the following description is a coordinate system based on the position of the acceleration sensor 9, and represents a state in which the x axis is parallel to the axis J of the front frame 22.

State (A) represents a state in which the steering angle is 0°, but the actual traveling direction of motor grader 100 is in the left front direction. Further, state (A) represents a state when the blade propulsion angle θ (the angle between the axis J and the blade 42) is 60°. In this case, based on the output from acceleration sensor 9, angle α indicating the actual direction of movement of motor grader 100 (direction of arrow 601) is −5°. One of the reasons why the angle α is not 0° is that the dynamic friction coefficient of the wheels 11 and 12 of the motor grader 100 varies depending on road surface conditions and the like.

Since the angle α indicating the actual traveling direction is −5°, even if the blade propulsion angle θ (the angle between the axis J and the blade 42) is 60°, the angle δ formed by the blade 42 with respect to the actual traveling direction (Angle δ (0≦δ≦180) between the X-axis and the blade 42) is 65° (=60°−(−5°)).

Note that in this situation, the angle α is defined as the angle between the x-axis and the actual traveling direction of the motor grader 100. Furthermore, the angle α is defined as positive or negative so that it takes a negative value when the actual traveling direction of the motor grader 100 has a component in the negative direction of the y-axis. However, these arrangements are just examples and are not limited thereto.

In state (A), after the operator turns on a predetermined switch 120 (see FIG. 6) in order to automatically control the blade propulsion angle θ, the traveling direction (actual traveling direction) of the motor grader 100 changes to the right forward direction. Assume that there has been a change (state (B)).

In this case, based on the output from the acceleration sensor 9, the angle α indicating the actual traveling direction of the motor grader 100 (the direction of the arrow 602) is 5°, as shown in state (B). Note that also in state (B), the steering angle is 0°.

Since the actual direction of travel has changed, motor grader 100 changes blade propulsion angle θ. The motor grader 100 changes the blade propulsion angle θ to follow changes in the actual direction of travel.

Specifically, motor grader 100 controls blade propulsion angle θ so that the following equation (1) holds true.

θ=γ+α… (1)
The target angle γ is the angle (fixed value) obtained by subtracting α from θ when the above-mentioned predetermined switch 120 is turned on. In this example, in the example of state (A), γ is 60° minus -5°. Specifically, in the example of state (A), γ is 65°.

In state (B), the angle α has changed from -5° to 5°, so the motor grader 100 changes the blade propulsion angle θ as shown in state (C) by referring to the above equation (1). Change from 60° to 70°. Since the angle α has increased by 10°, the motor grader 100 also increases the blade propulsion angle θ by 10°. Through such processing, the inclination of the blade 42 with respect to the X axis or the Y axis in state (A) and state (C) becomes the same.

Specifically, since the angle α indicating the actual direction of travel is 5 degrees, even if the blade propulsion angle θ (the angle between the axis J and the blade 42) is 70 degrees, the angle α representing the actual direction of travel is The angle δ is 65° (=70°-5°) as in state (A).

As described above, the motor grader 100 controls the blade propulsion angle θ of the blade 42 based on the output from the acceleration sensor 9 installed in the vehicle body 2. The motor grader 100 changes the blade propulsion angle θ according to the amount of angular change in the traveling direction of the motor grader 100. The motor grader 100 changes the blade propulsion angle θ by the same amount as the angular change amount in the traveling direction of the motor grader 100.

According to such a configuration, motor grader 100 (more specifically, the main controller) can determine the actual traveling direction of motor grader 100. Therefore, the motor grader 100 can accurately make the blade propulsion angle θ follow a change in the traveling direction of the motor grader 100.

In the example of FIG. 8, the process when the traveling direction (actual traveling direction) of the motor grader 100 changes after turning on the switch 120 when the steering angle is 0°, and the advantages obtained by the process will be explained. did. Such advantages are also obtained when the steering wheel is further rotated after turning on switch 120 when the steering wheel is in a non-neutral state. It is also obtained when the steering wheel is kept in the neutral position after turning on the switch 120 when the steering wheel is in the neutral state. In this manner, the motor grader 100 executes a process of automatically controlling the blade propulsion angle θ when the actual traveling direction changes from when the switch 120 was turned on.

The motor grader 100 is configured to determine the traveling direction using an acceleration sensor 9 installed on the front frame 22. Therefore, even when the motor grader 100 is working in an articulated state, the blade propulsion angle θ can accurately follow changes in the traveling direction of the motor grader 100. Further, even when the motor grader 100 is working while leaning the front wheels, it is possible to accurately make the blade propulsion angle θ follow a change in the traveling direction of the motor grader 100.

In this way, by attaching the acceleration sensor 9 to the front frame 22, it becomes possible to accurately make the blade propulsion angle θ follow a change in the traveling direction of the motor grader 100, regardless of the attitude of the motor grader 100. .

(Modified example)
FIG. 9 is a diagram for explaining another installation position of the acceleration sensor 9.

Referring to FIG. 9, acceleration sensor 9 is attached to drawbar 40. The acceleration sensor 9 is attached to the surface of the drawbar 40 so as to be located directly below the front frame 22 when the drawbar 40 is in the neutral position (the state shown in FIG. 2). Acceleration sensor 9 is attached to the rear side of swing motor 49.

Note that the acceleration sensor 9 may be attached to the front side of the swing motor 49. The acceleration sensor 9 may be attached to any location on the drawbar 40.

[Embodiment 2]
In this embodiment, a configuration will be described in which the automatic control of the blade propulsion angle described in Embodiment 1 is applied to a bulldozer. Hereinafter, descriptions of configurations that overlap with those in Embodiment 1 will not be repeated.

FIG. 10 is a perspective view of the bulldozer.

As shown in FIG. 10, bulldozer 300 includes a vehicle body 311 and a working machine 313. The vehicle body 311 includes a pair of left and right traction devices 316 (316R, 316L), a cab 341, and an engine compartment 342. The work machine 313 is provided in front of the vehicle body 311. The work machine 313 has a blade 318 for performing work such as excavating earth and sand and leveling the ground.

A pair of left and right traction devices 316 (316R, 316L) are devices for driving the bulldozer 300. The pair of left and right traction devices 316 (316R, 316L) include, for example, crawler belts and a final deceleration device. The bulldozer 300 travels by rotationally driving the pair of left and right traction devices 316 (316R, 316L).

An acceleration sensor 9 is attached to the vehicle body 311. Acceleration sensor 9 is attached to the surface of engine compartment 342. Note that the acceleration sensor 9 may be installed in the cab 341.

FIG. 11 is an enlarged view of the main parts of the bulldozer 300.

As shown in FIG. 11, the bulldozer 300 includes a ball joint 312, a U-shaped frame 317, a pair of lift cylinders 319 (319R, 319L), a pair of angle cylinders 321 (321R, 321L), It further includes a tilt cylinder 325 and a pitch rod 327. The pair of lift cylinders 319 (319R, 319L) and the pair of angle cylinders 321 (321R, 321L) are arranged at symmetrical positions with respect to the axis R of the frame 317.

Ball joint 312 rotatably connects blade 318 and U frame 317.

The pitch rod 327 can adjust the pitch of the blade 318. One end of the pitch rod 327 is connected to the blade 318 by a connecting member 329. The other end of the pitch rod 327 is connected to the frame 317 by a connecting member 328.

The bulldozer 300 raises or lowers the blade 318 by changing the stroke length of the lift cylinders 319 (319R, 319L). In the bulldozer 300, the blade propulsion angle θ of the blade 318 is changed by changing the stroke length of the angle cylinder 321 (321R, 321L).

FIG. 12 is a diagram for explaining the blade propulsion angle θ in the bulldozer 300.

Referring to FIG. 12, state (A) represents a state where the blade propulsion angle θ is 90°. In state (A), the virtual line V passing through the connecting member 328 and parallel to the Y-axis is parallel to the axis W1 of the blade 318.

In state (A), when the operator operates the operating lever for the angle cylinders 321 (321R, 321L), the blade propulsion angle θ changes. In this case, the angle formed by the axis R of the frame 317 and the axis W2 of the blade 318 after the change on the XY plane becomes the blade propulsion angle θ.

In this manner, the bulldozer 300 also performs work by setting the blade propulsion angle θ by the operator. Therefore, the automatic control of the blade propulsion angle described in the first embodiment can be applied to the bulldozer 300.

Therefore, the bulldozer 300 (more specifically, the controller (not shown ) of the bulldozer 300) can determine the actual direction of movement of the bulldozer 300. Therefore, the bulldozer 300 can accurately make the blade propulsion angle θ follow a change in the traveling direction of the bulldozer 300.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and it is intended that all changes within the meaning and range equivalent to the claims are included.

2,311 Vehicle body, 3 Cab, 4,313 Work equipment, 6,342 Engine compartment, 9 Acceleration sensor, 11 Front wheel, 12 Rear wheel, 21 Rear frame, 22 Front frame, 25 Exterior cover, 38 Angle sensor, 40 Drawbar, 41 swing circle, 42,318 blade, 44,45,319 lift cylinder, 46 drawbar shift cylinder, 47 blade shift cylinder, 48,325 tilt cylinder, 49 swing motor, 51 counterweight, 53 connecting shaft, 54 articulate cylinder, 92 leaning cylinder, 100 motor grader, 120 switch, 129 steering wheel , 1 46 starter switch, 150 main controller, 151 operation content determination section, 155 memory, 156 control valve control section, 171 sensor, 300 bulldozer, 312 ball joint, 316 Traction device, 317 Frame, 321 Angle cylinder, 327 Pitch rod, 328, 329 Connecting member, 341 Cab, C1 Rotating shaft, J, R, W1, W2 Axis line, K Center line, M1 First imaginary line, M2 Second imaginary line, V imaginary line.

Claims (14)

A work vehicle,
The car body and
A work machine having a blade,
The vehicle body includes a controller that controls the operation of the work machine and an acceleration sensor,
The controller includes:
Determining the traveling direction of the work vehicle based on the output from the acceleration sensor,
A work vehicle that changes a blade propulsion angle, which is a rotation angle of the blade in a plan view, in the same direction as the angle change in the traveling direction by the same amount as the angular change in the traveling direction . The vehicle body further includes an operating device for automatically controlling the blade propulsion angle ,
The controller controls the blade propulsion angle based on the output from the acceleration sensor on the condition that the operation device is operated to execute the automatic control. work vehicle. The work vehicle is a motor grader,
The vehicle body further includes a rear frame and a front frame rotatable with respect to the rear frame,
The work vehicle according to claim 1 , wherein the acceleration sensor is provided on the front frame. The work machine includes a turning circle that supports the blade, and an actuator that rotates the turning circle,
The work vehicle according to any one of claims 1 to 3 , wherein the controller controls the blade propulsion angle by operating the actuator. The work vehicle is a bulldozer,
The work machine further includes a blade angle cylinder,
The work vehicle according to claim 1 or 2 , wherein the controller controls the blade propulsion angle by operating the blade angle cylinder. The vehicle body further includes a cab,
The work vehicle according to claim 5 , wherein the acceleration sensor is provided in the cab. A work vehicle,
rotating circle and
a blade supported by the turning circle;
front frame and
a drawbar swingably attached to the front frame and to which the turning circle is attached;
an acceleration sensor provided on the drawbar;
By determining the traveling direction of the work vehicle based on the output from the acceleration sensor and rotating the turning circle, the blade propulsion angle, which is the rotation angle of the blade in plan view , is determined in the traveling direction. and a controller that changes the angle in the same direction as the angle change in the traveling direction by the same amount as the angle change amount in the traveling direction . A method for controlling a work vehicle, wherein the work vehicle includes a vehicle body and a work implement having a blade, the vehicle body includes a controller that controls operation of the work implement, and an acceleration sensor;
the controller receiving a signal output from the acceleration sensor;
the controller controls a blade propulsion angle, which is a rotation angle of the blade in plan view, based on the signal ;
The step of controlling the blade propulsion angle includes:
determining the traveling direction of the work vehicle based on the signal;
A control method comprising the step of changing the blade propulsion angle in the same direction as the direction of angular change in the traveling direction by the same amount as the amount of angular change in the traveling direction . In the step of controlling the blade propulsion angle, on the condition that an operation for automatically controlling the blade propulsion angle is performed on an operating device provided on the vehicle body for automatically controlling the blade propulsion angle. The control method according to claim 8 , wherein the blade propulsion angle is controlled based on an output from an acceleration sensor. 9. The work vehicle is a motor grader, and the vehicle body further includes a rear frame and a front frame rotatable with respect to the rear frame, and the acceleration sensor is provided on the front frame. Control method described in . The work machine has a turning circle that supports the blade, and an actuator that rotates the turning circle,
The control method according to any one of claims 8 to 10 , wherein in the step of controlling the blade propulsion angle, the controller controls the blade propulsion angle by operating the actuator. The work vehicle is a bulldozer, and the work machine further includes a blade angle cylinder,
10. The control method according to claim 8 , wherein in the step of controlling the blade propulsion angle, the controller controls the blade propulsion angle by operating the blade angle cylinder. The control method according to claim 12 , wherein the vehicle body further includes a cab, and the acceleration sensor is provided in the cab. A method for controlling a work vehicle, wherein the work vehicle includes a turning circle, a blade supported by the turning circle, a front frame, and a drawbar that is swingably attached to the front frame and to which the turning circle is attached. , an acceleration sensor provided on the drawbar, and a controller,
the controller receiving a signal output from the acceleration sensor;
The controller controls a blade propulsion angle, which is a rotation angle of the blade in a plan view , by rotating the turning circle,
The step of controlling the blade propulsion angle includes:
determining the traveling direction of the work vehicle based on the signal;
A control method comprising the step of changing the blade propulsion angle in the same direction as the direction of angular change in the traveling direction by the same amount as the amount of angular change in the traveling direction .

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